The royal baby boy has finally arrived! Kate Middleton gave birth to the future king yesterday afternoon at St. Mary's Hospital in London. An official document placed on a wooden easel right outside of Buckingham Palace said the baby weighed 8 pounds, 2 ounces. The only thing missing from the regal document was the name of the little boy.

According to several reports the name of the baby could be revealed as the Duchess of Cambridge leaves the hospital or within a few days of them arriving home. Picking the baby's name is a lengthy procedure for several reasons. One, the name has to be a traditional name since the royal baby could become a king one day; and two, there are several options for a last name Prince William and Kate Middleton can choose from.

According to the Washington Post, most royals don't actually have a last name and usually just take the name from their title as their last name. For example Prince William, the son of Charles, Prince of Wales, uses the last name of Wales. In the Royal Air Force he is known as Flight Lt. Wales and while in college he used the name William Wales. His brother, Harry, also uses Wales.

Prince William, however, does have an actual last name: Mountbatten-Windsor. According to Babble, before 1917 members of the Royal Family used the name of their dynasty or house to which they belonged as their only choice of a last name. That changed when George V adopted the name Windsor as his actual last name.

The tradition continued until Queen Elizabeth II, along with her husband The Duke of Edinburgh, wanted to distinguish their descendants from the rest of the Royal Family so they declared their last name as Mountbatten-Windsor. That combined the adopted family name by George V and the surname of the Queen's husband, Prince Phillips.

Sounds a little confusing for people who are not a part of the royal family. So when it comes time for Middleton and Prince William to pick a last name for their baby, they have a couple options. They could either opt out of the baby having a last name, they can pick Mountbatten-Windsor (which is uncommon) or they can use Wales. Because the couple had a royal house bestowed upon them once they got married, Cambridge, they can also choose that as their baby's name.

Obviously with so many choices, this process takes some time. The Royal Family's website, however, does say that the couple might end up going with the name Mountbatten-Windsor.